Asked by Rose whether Goldman investment advisers had ever bought securities from the firm, sold them to clients, and then bet against those same securities, Blankfein paused. And after a solid six seconds of silence, sought to explain that Goldman's role as a "market maker."

"We're like a machine, that lets people buy and sell what the want to buy and sell" Blankfein said. "That's not the advisory business. That's just a facility for market making."

Blankfein argued that there's no problem in selling clients a security that Goldman will then bet against, because that's the nature of the market.

"By the way, we would'nt even know," Blankfein said of the conflicting market positions.

On Friday, The Washington Post reported that the Justice Department's criminal investigation into Goldman's trading was more broad than that of the SEC's probe.